Basic Reporting Data, 5-6. Werlich refers to the procedure as a “VOR penetration.” VOR is the acronym for VHF Omni-directional Radio Range, which in combination with Distance Measuring Equipment (DME) provides range and bearing information for civil aviation, comparable to, though less accurate than, the military’s Tactical Air Navigation system (TACAN). “Penetration” is a colloquial term that refers to departing FL200 and “penetrating” the airspace under the control of Minot AFB radar approach control (RAPCON).